Chain door lock



y 6, 1970 E. E. SCHAEFER 3,514,143

CHAIN DOOR LOCK Filed Nov. 5, 19 68 2 Sheets-Sheet l May 26, 1970 Filed Nov. 5, 1968 CHAIN DOOR LOCK 2 Sheets-Sheet 2 a mu 5% 155 154 HIIIIIIII J62 177 1741 173 5Z Invenfir- Edwanil'Sckaefer g w w gww United States Patent 3,514,143 CHAIN DOOR LOCK Edward E. Schaefer, 1134 Oak Knoll Drive, Lake Forest, Ill. 60045 Continuation-in-part of application Ser. No. 652,552, July Ill, 1967. This application Nov. 5, 1968, Ser. No. 777,984

Int. Cl. Ec 17/36 US. Cl. 292-464 12 Claims ABSTRACT OF THE DISCLOSURE A chain door lock including a door bracket for mount-- ing on a door, a door frame bracket for mounting on structure adjacent the door, and a chain for detachably interconnecting the door and door frame brackets. One end of the chain is retained by the door frame bracket and the other end of the chain is detachably connected to the door bracket when positioned in a channel in the door bracket. Movement of the chain into or out of the channel to render the device operative or inoperative is achieved by a key element in the chain and an opening in the door bracket which extends into the channel and which will only permit passage of the key element.

This application is a continuation-in-part of the Edward E. Schaefer application, Ser. No. 652,552, filed July 11, 1967, now abandoned.

This invention relates generally to door locking devices, and more particularly relates to an improved chain-type safety door lock.

Various types of chain door locks have been heretofore developed for limiting the extent to which a door may be opened while still providing a degree of safety against entry by intruders. While many of such devices have proved satisfactory for their intended purpose, others have not for various reasons, such as difliculty of release or unlocking, complexity of construction and/or operation, and high cost.

Briefly described, the present invention contemplates a novel chain door lock which permits partial opening of a door with which the device is associated and which precludes unintentional unlocking or release of the lock from outside the door. The chain door lock to be hereinafter described in detail includes a retaining means or bracket adapted to be secured to a door, a mounting means or bracket adapted to be secured to structure adjacent the door, such as the door frame, and elongated flexible means, such as a chain, having one end retained by the door frame bracket. An abutment is provided at the other end, or at an intermediate point in the chain, to prevent disengagement of the chain from the door bracket when the chain is positioned in a channel in the door bracket.

In order to permit the chain to be shifted into or out of the channel in the door bracket to render the device operative or inoperative, interfitting means is provided. Such interfitting means preferably comprises an opening in the door bracket and extending into the channel therein, and a key element intermediate the length of the chain and shiftable through the opening in the door bracket. The opening and key element are dimensioned so that only the key element can pass through the slot into the channel.

In one embodiment, the retaining means and abutment include complementally shaped portions which coact to substantially prevent disengagement of the abutment from the retaining means when these parts are engaged.

In another embodiment, the retaining means includes a tubular portion, and the interfitting means comprises a slot in the tubular portion and a key element in the elongated flexible means, the key element being movable through the slot to permit the flexible means to be shifted into or out of the channel in the tubular portion of the retaining means In a further embodiment, the channel in the retaining means includes at least one and preferably a pair of substantially planar surface portions which define a convergent exit passage leading toward the slot and serving to guide the key element toward the slot so that the lock maybe quickly rendered inoperative.

In still another embodiment, the retaining and mounting means each include a channel for receiving different portions of the elongated flexible means, and a slot is provided in one of the retaining and mounting means to permit the key element to pass through the slot to render the lock operative or inoperative. In this embodiment, an abutment is provided at each end of the elongated flexible means to prevent the ends from passing through the channels in the respective retaining and mounting means and, since the elongated flexible means is freely shiftable in the channels in the retaining and mounting means, the effective length of the elongated flexible means may be shortened. When the lock is inoperative, such shortening is accomplished by pulling a portion of the elongated flexible means through the channel in the other or the retaining and mounting means and then permitting such portion to hang downwardly from such other means.

A notch is provided in the other of the retaining and mounting means for receiving and retaining a portion of the elongated flexible means intermediate the ends thereof. Such notch thus maintains the elongated flexible means in an effectively shortened condition and consequently limits the extent to which the associated door may be opened when the device is in operation.

Accordingly, it is a general object of the present invention to provide a novel and improved chain-type door lock.

Another object is to provide a novel chain door lock which cannot be easily released or unlocked by an intruder from outside the door.

A further object is to provide a novel chain door lock of the foregoing character, which is simple in construction, reliable in operation, attractive in appearance, and low in cost.

Objects and advantages of the invention will be apparent from the following detailed description and accompanying sheet of drawings, in which:

FIG. 1 is a front elevational view of a chain door lock embodying the features of the present invention and showing the parts thereof as they would appear when the lock is in operation and mounted on an associated door and adjacent structure;

FIG. 2 is a somewhat enlarged top plan view of the lock shown in FIG. 1;

FIG. 3 is a somewhat enlarged vertical sectional View, with some parts in elevation, taken along the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary front elevational view of the lock shown in FIG. 1, and showing the parts thereof in the position they would occupy when positioned to render the lock operative or inoperative;

FIG. 5 is enlarged horizontal sectional view taken substantially along the line 55 of FIG. 4;

FIG. 6 is a fragmentary front elevational view of a portion of the chain door lock illustrated in FIGS. 1 and 4, and showing an alternate construction for one of the parts thereof;

FIG. 7 is a broken, front elevational view of another chain door lock embodying the features of the present invention;

FIG. 8 is a fragmentary horizontal sectional view taken substantially along the line 8-8 of FIG. 7;

FIG. 9 is a broken, front elevational view of another chain door lock embodying the features of the present invention;

FIG. 10 is a sectional view along the line 1010 of FIG. 9;

FIG. 11 is a front elevational view of another chain door lock embodying the features of the present invention and showing the parts thereof as they would appear when in an operative position;

FIG. 12 is a fragmentary front elevational view of a portion of the lock shown in FIG. 11, and showing the parts thereof as they would appear when positioned to render the lock operative or inoperative;

FIG. 13 is a sectional view taken along the line 1313 of FIG. 12;

FIG. 14 is a front elevational view of the lock shown in FIG. 1, but showing the parts thereof as they would appear when in another operative position; and

FIG. 15 is a front elevational view of the lock shown in FIG. 1, but showing the parts thereof as they would appear when the lock is inoperative.

In FIGS. 1 through 5, a chain door lock 10 embodying the features of the present invention, is illustrated. The lock 10 preferably comprises retaining means in the form of bracket 11 that is adapted to be secured to the inner side, indicated at 12, of a door 13, as by screws 14, and mounting means in the form of another bracket 16 that is adapted to be secured as by screws 17 to structure adjacent the door 12, such as a door frame or molding 18.

For detachably interconnecting the door bracket 11 and door frame bracket 16 to thus provide a lock for the door 13, elongated flexible means in the form of a chain 20 is provided. The chain 20 includes a plurality of interconnected links 21 and, in this instance, has one end 22 thereof secured to the door frame bracket 16- as by U- shaped shackle 23 having its legs 24 fixedly mounted in the door frame bracket 16, with one of the legs 24 extending through the link 22.

The opposite or other end, indicated at 26, of the chain 20, includes an abutment or stop, indicated generally at 30, for engaging the door bracket 11 and preventing disengagement of the other end 26 of the chain 20- from the door bracket when the device is operative. It will be understood that the abutment 30 could be located at an intermediate point in the chain 20, rather than at the end 26 thereof, or could be movably mounted thereon in order to permit shortening or lengthening of the effective length of the chain.

As best seen in FIGS. 1 and 3, the abutment 30 includes a pyramidally shaped upper portion 32 and a lower and somewhat smaller pilot portion 33 defining at least one shoulder 34 therebetween. The pilot portion 33, in the present instance, is cylindrical, and, since the base of the upper or pyramidal portion 32 is rectangular (FIG. 2), four symmetrically spaced shoulders 34 are defined on the underside of the base of the pyramidal portion 32.

In order to permit the pilot portion 33 to extend into the door bracket 11, the latter includes a channel defined by a vertically extending cylindrical bore 36 (FIGS. 3 and 5) therethrough. The upper end of the bore 36 intersects a rectangularly-shaped depression 38 (FIGS. 4 and 5) in the bracket 11 so that at least one, and in the present instance, four symmetrically spaced ledges 42 are defined by the areas between the corners of the depression 38 and the bore 36 at the intersection of the latter with the former. The ledges 42 thus comprise a seat for the four symmetrically spaced shoulders 34 on the underside of the pyramidal portion 32, when the abutment 30 is fully engaged with the door bracket 11, as shown in FIGS. 1, 2 and 3. At least two of the spaced walls, indicated at 43, of the rectangularly-shaped depression 38 may be chamfered or beveled to facilitate movement of the pilot portion 33 of the abutment 30 into the bore 36 and engagement of the shoulders 34 on the underside of the pyramidal portion 32 with the ledges 42 of the bracket 11.

4 Thus, when the pilot portion 33 extends fully into the bore 36 in the bracket 11 so that the shoulders 34 on the abutment 30 rest on the ledges 42, displacement of the abutment 30 from such seated position on the door bracket 11 cannot be readily accomplished by an intruder working from outside of the door 13.

Movement of the chain into or out of the :bore 36 in the door bracket 11 to render the lock 10 operative or inoperative is achieved by interfitting means carried by the bracket 11 and chain 20. Such interfitting means preferably comprises an opening in the form of a slot 52 in the bracket 11, which extends into the bore 36, and a key element in the form of a specially formed link 53 in the chain 20.

As best seen in FIG. 5, the width of the slot 52 is somewhat greater than the thickness of the material of the link 53 but less than the thickness of the material of the remainder of the links of the chain 20. Consequently, only the link 53 of the chain 20 may pass through the slot 52, as illustrated by the full line position of the link 53 in FIG. 4 and by the broken line position of the link 53 in FIG. 5. However, since the diameter of the bore 36 in the bracket 11 is somewhat greater than the effective diameter of the links 21 of the chain 20, the latter is freely shiftable in the bore 36. Because the link 53 is the only link of the chain 20 that will pass through the slot 52, the link 53 is preferably positioned in the chain 20 toward the end 22 thereof secured to the door frame bracket 16. The link 53 thus cannot be manipulated through the slot 52 from outside the door 13.

The link 53 shown in FIGS. 1, 4 and 5 is in the form of a closed loop having spaced, parallel sides which are circular in cross section. However, the link 53 could be of some other shape, if desired, so long as it includes a portion or portions which are the only portions capable of being shifted through the slot 52 into and out of the bore 36. If some other shape is utilized, at least the outer surface portions of the sides of the link are preferably rounded to facilitate free movement of the link through the slot.

In FIG. 6, a key element or link 56 is illustrated, WhlCh could be utilized in place of the link 53 shown in FIGS. 1, 4 and 5. The link 56 is in the form of a twisted S-hook having a longitudinally extending or straight central portion 57 and end portions 58 and 59 bent into loops that extend through the openings in adjacent links 21 of the chain 20. In addition, a link formed from plate stock and having openings at each end thereof could also be employed in place of the link 53. Moreover, while the central portion 57 of the link 53 is preferably circular in cross section, other shapes could also be utilized, as, for example, triangular, rectangular, hexagon, etc. However, regardless of the cross sectional shape of the portion 57, the eifective diameter or greatest thickness of such portion must be less than the width of the slot 52 so that the portion 57 can pass through the slot 52 regardless of the rotated position of the portion 57 with respect to its longitudinal axis. In other words, the portion 57 may be of any cross sectional shape so long as it will pass through the slot 52 in the bracket 11 without regard to the position of the link when the portion 57 thereof is shifted through the slot 52. Such construction is far superior to prior art locks of this type, wherein a key link having a configuration diiferent from the other links of the chain is utilized to render the lock inoperative by passage of the link through a slot in a retaining member and wherein the key link will pass through the slot only when it is in a certain rotated position with respect to the slot.

The fact that the portion 57 of the link 53 can be rapidly and easily manipulated through the slot 52 of the bracket 11, in any rotated position of the portion 57 with respect to its longitudinal axis, provides a significant and highly important safety feature in the operation of a chain door lock incorporating such a key element, namely, rapid unlocking of a door with which the lock is associated under emergency conditions.

Thus, should a fire or other emergency condition arise in a dwelling having a door lock associated with the door thereof, such as the door lock having the key element or link 56 in the chain thereof, the door can be easily and rapidly unlocked to permit the occupants to rapidly evacuate the premises. Such ease of unlocking or release may also be accomplished under unfavorable lighting conditions and even in total darkness, which is frequently the case in an emergency situation. In other words, utilization of the key element or link 56 shown in FIG. 6 in place of link 53 in the chain 20 the door lock 10 insures that the dwelling with which the lock is used will not become a fire trap or prison under emergency conditions.

Moreover, since the construction of a door lock utilizing the link 56 is simple in comparison to many of the prior art locks, the mode of operation thereof is readily apparent from the device itself. Consequently, the lock 10 utilizing the link 56 may be used by children and aged or infirm adults. In addition, such simplicity of construction and operation eliminates the need for anything but the most elemental of instructions as to the operation of the lock.

In FIGS. 7 and 8, another chain door lock 60 embodying the features of the present invention, is illustrated. Like reference numerals have been used to identify parts identical with those heretofore described. The lock 60 thus comprises retaining means in the form of a bracket 61 that is adapted to be secured to the inner side, indicated at 12, of the door 13, mounting means in the form of a bracket 62 that is adapted to be secured to structure adjacent the door 12, such as a door frame or molding 18, and elongated flexible means in the form of a chain 20 for detachably interconnecting the brackets 61 and 62.

The door frame bracket 62 comprises a rectangularlyshaped plate which may be secured to the inner side of the door 12 as by screws 64. A rivet having an enlarged head 65 and a shank 66, is mounted on the plate and connects one end 22 of the chain 20 thereto, the shank 66 extending through the link 22 and being centrally secured in the plate.

The door bracket 61 also comprises a rectangularlyshaped plate secured to the inner side of the door 12 as by screws 64. A tubular member in the form of a sleeve or bushing 70 is centrally secured to the plate as by a rivet 71. Other suitable types of fasteners could be used in place of the rivet 71, if desired.

In order to prevent the opposite or other end, indicated at 26, of the chain 20 from passing through the sleeve 70, means in the form of an abutment is provided on the end 26 of the chain for engaging the sleeve 70 when the lock is operative. The abutment 80 may be of any desired shape and construction, but as shown comprises a short, hour-glass shaped button having a fiat, circular undersurface 81 of somewhat greater diameter than the diameter of the channel or bore, indicated at 82, of the sleeve 70 so that the undersurface 81 will seat on the upper axial end face, indicated at 83, of the sleeve 70. While the abutment 80 is shown secured to the end link 26 of the chain 20 by a hook 83 mounted in the abutment 80, the latter could also be located at some other point in the chain 20 or be movably mounted thereon.

Engagement of the chain 20 with the door bracket 61 to render the lock 60 operative, or disengagement of the chain 20 therefrom to render the lock 60 inoperative, is achieved by interfitting means carried by the sleeve 70 and chain 20. Such interfitting means preferably comprises an opening in the form of a slot 86 formed by a split or gap in the sleeve 70, and a key element in the form of a specially formed link 53 in the chain 20. The width of the slot 86 is somewhat greater than the thickness of the material of the link 53 but less than the thickness of the material of the remainder of the links 21 of the chain 20. Consequently, only the link 53 may pass through the slot 86 in the sleeve 70, as illustrated in FIG. 7. However, since the diameter of the channel in the sleeve 70 is somewhat greater than the effective diameter of the links 21 of the chain 20, the latter is freely shiftable in the sleeve 70. Thus, since the link 53 is the only link which will pass through the slot 86, the link 53 is preferably positioned in the chain toward the end 22 thereof, as previously described. Consequently, manipulation of the link 53 through the slot 86 from outside the door 13 is virtually impossible.

In FIGS. 9 and 10, another chain door lock 90 embodying the features of the present invention, is illustrated.

The lock 90 comprises retaining means in the form of a bracket 91 that is adapted to be secured to the inner side, indicated at 12, of a door 13, as by screws 92, and mounting means in the form of another bracket '93 that is adapted to be secured to structure adjacent the door 12, such as a door or molding 18, as by screws, such as the screws 92.

For releasably interconnecting the door bracket 91 and door frame bracket 93, elongated flexible means in the form of a chain 100, is provided. The chain includes a plurality of interconnected links 101, only fragments of which are shown in FIGS. 9 and 10, and has one end 102 thereof secured to the door frame bracket 93 as by a rivet 103 having an enlarged head 104.

An abutment or stop 106 is secured to the other or, opposite end (not shown) of the chain 100, for engaging the door bracket 91 and preventing disengagement of such, other end from the door bracket 91 when the lock is in operation. The abutment 106 may be of any desired shape and construction but preferably comprises an upper head portion 107 and a lower and somewhat smaller pilot portion 108 defining an annular shoulder 109 therebetween. The pilot portion 108, in the present instance, is cylindrical, but could be of other cross sectional configurations if desired.

In other to permit the pilot portion 108 of the abut,

ment 106 to extend into the door bracket 91 and to provide a seat for the shoulder 109 of the abutment, the bracket 91 includes means defining a channel 110 therethrough for receiving the pilot portion 108 of the abutment 106 and a seat for the shoulder 109. The bracket 91, in the present instance, comprises a central or channel defining portion 112 and a pair of vertically arranged platelike portions or ears 113 extending above and below the channel defining portion 112 at the rear or door side thereof. The mounting portions or ears 113 are provided with openings for receiving screws, such as the screws 92, for securing the bracket 91 to the door 13.

The channel defining portion 112 is generally rectangular in cross section and includes a pair of laterally spaced side portions or arms 114 and 115 which extend outwardly or away from the door side of the bracket. The inner surface, indicated at 116, of the arm 114 is planar or substantially planar and is spaced from the inner surface, indicated at 117, of a parallel portion of the arm 115 by an amount substantially equal to and preferably somewhat greater than the diameter of the pilot portion 108 of the abutment 106. Consequently, the pilot portion 108 of the abutment 106 is extendable into the channel 110 in the portion 112 of the bracket 91.

In order to provide for movement of the chain 100 into or out of the channel 110 in the portion 112 of the bracket 91 to render the lock 90 operative or inoperative, interfitting means carried by the bracket 91 and chain 100 are provided. Such interfitting means comprises an opening or slot in the portion 112 and a key element in the chain 100. The opening or slot in the portion 112 is indicated at in FIG. 10 and is defined by a gap between the outer end, indicated at 118, of the arm 114 and the adjacent end, indicated at 119, of a laterally extending flange or arm 121 on the outer portion of the arm 115.

The key element comprises a specially formed link in the chain 100, that is preferably in the form of an S-hook 122. The hook 122 includes a longitudinally extending or straight central portion 123 and spaced end portions 124 and 125 which are bent into loops and connected to adjacent links of the chain 100. At least the central portion 123 of the link 122 has an effective diameter or thickness that is greater than that of the other links of the chain 100 and substantially equal to and preferably somewhat less than the width of the gap 120 in the portion 112 of the bracket 91. Consequently, only the link 122 of the chain 100 will pass through the slot 120, as illustrated by the full line position of the link 122 in FIG. 9 and by the broken line position of the link 122 in FIG. 10.

Since the effective diameter of the channel 110 or interior of the portion 112 is somewhat greater than the effective diameter of the links of the chain 100, the chain is freely shifta'ble in the channel 110. In addition, while the central portion 123 of the link 122 is preferably circular in cross section, other shapes could be utilized. However, regardless of the cross sectional shape employed, the effective diameter or greatest thickness of the central portion 123 must be less than the width of the slot 120 so that the central portion 123 can pass through the slot 120 regardless of the rotated position thereof with respect to its longitudinal axis. Such construction is far superior to prior art locks of this type, wherein a key link having a configuration different from the other links of the chain is utilized for passage through a slot in a retaining mem; her to render the lock inoperative and wherein the key link will pass through the slot only when it is in a certain rotated position with respect to the slot. Moreover, since the link 122 is the only link of the chain 100 that will pass through the slot 120, the link 122 is preferably positioned toward the end 102 of the chain. Such arrangement prevents manipulation of the link 122 through the slot 120 from outside the door 13.

The fact that the portion 123 of the link 122 can be rapidly and easily manipulated through the slot 120 of the bracket 91, in any rotated position of the portion 123 with respect to its longitudinal axis, provides a significant and highly important safety feature in the operation of the door lock 90, namely, rapid unlocking of a door with which the lock is associated under emergency conditions.

Thu, should a fire or other emergency condition arise in a dwelling having the lock 90 associated with the door thereof, the door can be easily and rapidly unlocked to permit the occupants to rapidly evacuate the premises. Such ease of unlocking or release may be accomplished under unfavorable lighting conditions and even in total darkness, which, is frequently the case in emergencies. In other words, key element 122 in the chain 100 insures that the dwelling with which the lock 90 is used will not become a fire trap or prison under emergency conditions.

Moreover, since the construction of the door lock 90 is simple, in comparison to many of the prior art locks, the mode of operation thereof is readily apparent from the device itself. Consequently, the lock 90 may be used by children and aged or infirm adults. In addition, such simplicity of construction and operation of the lock 90 eliminates the need for anything but the most elemental of instructions as to its operation.

In order to facilitate rapid movement of the link 122 through the slot 120 in the bracket 91 to render the lock 90 inoperative, the portion 122 includes at least one and preferably a pair of planar or substantially planar surface portions which define a convergent exit passage in the channel 110 and leading toward the slot 120. To this end, the flange or arm 121 increases in thickness from the end 119 thereof toward the arm 115 so that the inner surface, indicated at 126, of the flange or arm 121 is planar or substantially planar, and inclined with respect to the inner surface 116 of the arm 114. The surface 126 thus comprises at least one planar or substantially planar surface portion defining the convergent exit passage. The inner surface 116 of the arm 114 comprises another planar or substantially planar surface portion of the passage.

Thus, assuming that the chain is positioned in the channel of the bracket 91 with the shoulder 109 resting on the upper surface, indicated at 127 (FIG. 9), of the portion 112 and it is desired to disconnect the chain from the bracket 91 in order to permit the door 13 to be fully opened, the abutment 106 is grasped and pulled upwardly until the link 122 of the chain is in the position thereof illustrated in FIG. 9 with the straight portion 123 of the link 1 22 in substantial vertical alignment with the slot 120. The abutment 106 is then shifted outwardly or away from the door 13 so as to cause the link 122 to shift in the channel 110 toward the slot 120. In the event that the central portion 123 of the link 122 is not in perfect lateral alignment with the slot 120, it will contact the inclined surface portion 126 of the flange 121 and be guided thereby toward the slot 120 with a minimum amount of manipulation in the part of the user.

While it is desirable to be able to effect rapid disengagement of the chain 100 from the channel 110 and the door bracket 91 in order to quickly render the lock 90 inoperative, the converse is also true. To this end, the adjacent ends 118 and 119 of the arm 114 and flange 121, respectively, are rounded to provide an enlarged entrance into the slot 120. Such enlarged entrance facilitates passage of the central portion 123 of the link 122 through the slot 120 and into the channel in the bracket 91.

In the foregoing description of the bracket 91 of the lock 90, the inclined inner surface portion 126 of the channel 110 has been described as being provided by the increasing thickness of the flange or arm 121. However, the inclined surface portion 126 could also be provided in other ways, such as by eliminating the flange or arm portion 121 and bending or otherwise inclining the outer portion of the arm so that the inner surface of such outer portion defines the surface portion 126.

Moreover, while the inner surface 126 of the flange 121 is the only surface of the exit passage of the channel 110 in the bracket 91 that is inclined with respect to the usual path of movement of the key link 122 when the latter is being shifted outwardly in the channel 110 toward the slot 120, an oppositely inclined pair of such inner surface portions could also be provided. In such a modification, the flange 121 of the arm 115 would be eliminated and the arms 114 and 115, or at least the outer portions thereof, would be bent or inclined inwardly or toward each other so that the inner surfaces of the arms, or the bent portions thereof, would each be oppositely inclined with respect to the usual outward direction of movement of the link 122 in the channel 110 as the link is moved toward the slot for disengagement from the channel.

In FIGS. 11-15, another chain door lock 130 embodying the features of the present invention, is illustrated. The lock 130 comprises retaining means in the form of a bracket 131 having a plate portion 132 that is adapted to be secured to the inner side, indicated at 12, of a door 13, as by screws and mounting means in the form of another bracket 133 having a plate portion 134 that is adapted to be secured as by screws 135 to structure adjacent the door 12, such as a door frame or molding 18.

For releasably interconnecting the door bracket 131 and door frame bracket 133 to render the lock 130 operative, elongated flexible means in the form of a chain having a plurality of interconnected links 141, is provided. A pair of abutments or stops 151 and 153 are respectively secured to the end links, indicated at 156 and 157, of the chain 140, and serve to prevent disengagement of the ends of the chain from the brackets 131 and 133 when the lock 130 is in operation.

Each of the abutments 151 and 153 includes an upper, generally egg-shaped head portion 162 and a lower and somewhat smaller diameter pilot portion 163. The pilot portion 164, in the present instance, is cylindrical and defines an annular shoulder 164 on the abutment. However, the pilot portion 164 could be of some other cross sectional configuration, if desired.

In order to provide for the retention of each of the abutments 151 and 153 in their respective brackets 131 and 133, each bracket includes a tubular, channel form ing portion 165 defining a channel for receiving the pilot portion 163 of the abutment and a seat to be engaged by the shoulder 164 of the abutment. Such channel forming portion, in the present instance, comprises a pair of laterally spaced, arcuate arms 166 and 167 which are preferably integrally formed with the plate portions 132 and 134 of their respective brackets 131 and 132. The arms 166 and 167 of each bracket define a channel therein of substantially circular cross section, and the upper end faces, indicated at 172 of each pair of arms comprise seats for the shoulders 164 of the respective abutments.

In order to permit a portion of the chain 140 to be shifted into and out of the channel in one Or the other of the door and door frame brackets 131 and 133 to render the lock 130 operative or inoperative, interfitting means carried by the door bracket 131 and chain 140 are provided. Such interfitting means comprises an opening or slot in the bracket 131 and a key element in the form of a key element in the chain 140.

The opening or slot, indicated at 170, in the bracket 131 is defined by a gap between the outer ends of the arms 166 and 167, and the key element is provided by a specially formed link 173 in the chain 140.

The key element or link 173 is preferably in the form of an S-hook having a longitudinally extending or straight central portion 174 and end portions 176 and 177 which are bent into loops and connected to adjacent links of the chain 140. At least the central portion 174 of the link 173 has an effective diameter or thickness that is less than that of the other links of the chain 140 and slightly less than the width of the slot 170 in the channel defining portion 165 of the bracket 131. Consequently, only the link 173 of the chain 140 will pass through the slot 170, as illustrated by the full line position of the link 173 in FIGS. 12 and 13 and the broken line position of the link 173 in FIG. 13. The internal diameter of the channel in the portion 165 of the brackets 131 and 133 is somewhat greater than the effective diameter of the links of the chain 140 so that the latter is freely shiftable in the channels in the brackets. Since the link 173 is the only link of the chain 140 that will pass through the slot 170, the link 173 is preferably positioned toward the end 157 of the chain. Such arrangement prevents manipulation of the link 173 through the slot 170 from outside the door 13. Such construction is far superior to prior art locks of this type, wherein a key link having a configuration different from the other links of the chain is utilized to render the lock inoperative by passage of the link through a slot in a retaining member and wherein the key link will pass through the slot only when it is in a certain rotated position with respect to the slot.

The fact that the portion 174 of the link 173 can be rapidly and easily manipulated through the slot 170 of the bracket 131, in any rotated position of the portion 174 with respect to its longitudinal axis, provides a significant and highly important safety feature in the operation of the lock 130, namely, rapid unlocking of the door with which the lock 130 is associated under emergency conditions.

Thus, should a fire or other emergency condition arise in a dwelling having the lock 130 associated with the door thereof, the door can be easily and rapidly unlocked to permit the occupants to rapidly evacuate the premises. Such ease of unlocking or release can be accomplished under unfavorable lighting conditions and even in total darkness, which is frequently the case in an emergency situation. In other words, the key link 173 in the chain 140 of the door lock 130 insures that a dwelling with which the lock is used will not become a fire trap or prison under emergency conditions.

Moreover, since the construction of the door lock 130 is simple in comparison to many of the prior art locks, the mode of operation thereof is readily apparent from the device itself. Consequently, the lock 130 may be used by children and aged or infirm adults. In addition, such simplicity of construction and operation eliminates the need for anything but the most elemental of instructions as to the operation of the lock 130.

While the central portion 174 of the link 173 is preferably circular in cross section, other cross sectional shapes could be utilized. However, regardless of the cross sectional shape of the portion 174, the effective diameter or greatest thickness of such portion must be less than the width of the slot 17 0 so that the portion 174 can pass through the slot regardless of the rotated position of the portion with respect to its longitudinal axis.

In order to facilitate movement of the link 173 through the slot 170 into the channel in the bracket 131, the lower corners of the adjacent ends of the arms 166 and 167 are beveled as at 177 (FIGS. 12, 15) to define an enlarged entrance into the slot 170.

With the foregoing construction, it will be apparent that when the shoulders 164 of the abutments 151 and 153 rest on the upper end faces 172 of the channel forming portions 165 of the brackets 131 and 133 with the pilot portions 163 disposed in the channels of their respective brackets in the manner illustrated in FIG. 11, the abutments 151 and 153 cannot be easily displaced from their seated positions on the portions 165 by an intruder working from outside the door 13. The lock 130 is thus rendered more positive in its action. It will also be apparent from FIG. 11 that the extent to which the door 13 may be opened, when the lock 130 is operative, is limited by the length of the chain 140. However, the extent to which the door 13 may be opened when the chain is taut may be greater than desired under certain conditions.

Accordingly, the lock 130 includes means for shortening the effective length of the chain 140 and consequently the extent to which the door 13 may be opened. Such means preferably comprises a recess or notch 171 in the channel forming portion of the bracket 133 for receiving and retaining a link of the chain 140. The notch 171 is preferably formed in the channel forming portion 165 of the bracket 133 by removing a portion of the material from the ends of the arms 166 and 167 so that the notch 171 extends into the portion 165 from the upper surface 172 and has a width substantially equal to the thickness of the material of the links 141 of the chain 140. The ends of the arms 166 and 167 are in contact with each other along a common interface 175.

Thus, when it is desired to limit the extent to which the door 13 may be opened when the lock 130 is in operation, a user need only lift the abutment 153 from its seated position on the channel forming portion 165 to cause the links of the chain 140 to move upwardly through the channel in the bracket 133. After a certain number of links have passed through the channel to provide the desired degree of shortening of the eifective length of the chain 140, the portion of the chain above the bracket 133 is swung downwardly so that a link thereof, indicated at 141, is caused to move into the notch 171 in the manner illustrated in FIG. 14. When so positioned, the link 141 becomes interlocked in the notch 171. Consequently, the chain 140 cannot be shifted in the channel in the bracket 133 and the length of the chain 140 is effectively shortened. It will be understood that any of the links of the chain 140, including the key link 173, may be shifted into the notch 171 in order to shorten the effective length of the chain.

When it is desired to disengage the link 141' from the notch 171 in order to utilize the full length of the chain 140, a user need only grasp the abutment 153 and swing the latter upwardly so as to lift the link 141 out of the notch 171. Thereafter, the abutment 153 is lowered to its seated position on the upper surface 172 of the channel forming portion 165 and the full length of the chain 140 is available to permit the door 13 to be opened to the maximum extent permitted by the length of the chain 140.

Assuming that the lock 130 is inoperative with the abutment 151 disengaged from the bracket 133 and the chain 140 hanging full length from the bracket 133, the chain is apt to be bumped or rattled by persons moving through the doorway. Such bumping or rattling may, in time, result in damage to the door frame 18 and/or door 13, and is annoying. Accordingly, the notch 171 may also be utilized to reduce the effective length of the chain 140 when the lock 130 is inoperative and thus entirely or at least substantially eliminate the aforementioned problems.

Thus, when the lock 130 is inoperative and the parts thereof are positioned as previously described, i.e. with the chain 140 hanging full length from the door frame bracket 137, the effective length of the chain 140 may be shortened merely by lifting the abutment 153 so as to cause a portion of the chain 140 to be pulled upwardly through the channel in the bracket 133 and then swinging the portion of the chain that has been pulled through the channel downwardly into juxtaposition with the portion of the chain below the bracket 133. Such relationship is illustrated in FIG. 15. During such downward swinging movement, the center link, indicated at 141", of the chain is moved into the notch 171. When the link 141" is positioned in the notch 171, the shortened effective length of the chain 140 will be maintained, even though the chain is subjected to vibration and jarring from frequent opening and closing of the door 13. In addition to the foregoing advantage, shortening of the effective length of the chain 140 when the lock 130 is inoperative also improves the aesthetic appearance of the lock 130.

While the thickness of the material of the key elements or links 53, 56, 122 and 173 of the chains 20, 100 and 140 has been herein illustrated and described as being somewhat less than the width of the slots 52, 86, 120 and 170 in the brackets 11, 61, 91 and 131, respectively, the thickness of the material of the links 53, 56, 122 and 173 could be the same as or greater than the thickness of the material of the other links of the chains 20, 100 and 140, so long as the links 53, 56, 122 and 173 are the only links which can pass through the slots 52, 86, 120 and 170. That is, the links 53, 56, 122 and 173 could have a special configuration such that only these links could pass through the slots 52, 86, 120 and 170 in their respective brackets, regardless of the size or configuration of the other links of the chains.

In addition, while the brackets 11, 61, 91 and 131 have been herein illustrated and described as being mounted on an associated door 13, and while the brackets 16, 62, 93 and 133 have been herein illustrated and described as being mounted on structure adjacent the door 13, such as the door frame 18, the mounting of such brackets could be reversed. That is, the present invention also contemplates mounting of the brackets 11, 61, 91 and 131 on structure adjacent the door 13, such as the door frame 18, and mounting of the brackets 16, 62, 93 and 133 on the door 13 instead of on the door frame 18.

Moreover, while the ends 22 of the chains have been herein illustrated and described as being permanently secured to the brackets 16 and 62, and while the end 102 of the chain 100 has been herein illustrated and described as being permanently secured to the bracket 93, such ends could also be detachably connected to the brackets or be movable relative thereto so as to permit disengagement of the chains 20 and 100 therefrom. In such a modification, the door frame brackets 16, 62 and 93 could be provided with channels therethrough of sufficient size to permit passage of the abutments 30, and 106, and the ends 22 and 102 of the chains could be provided with abutments of somewhat greater size or of a different configuration than the abutments 30, 80 and 106 so as to prevent disengagement of the ends 22 of the chains 20 from the door frame brackets 16 and 62 and disengagement of the end 102 of the chain from the door frame bracket 93 when the locks are in operation.

I claim:

1. A door lock comprising retaining means adapted to be secured to one of a pair of door and frame members, mounting means adapted to be secured to the other of said members, one of said retaining and mounting means having a channel therein and an opening extending into said channel, said one of said retaining and mounting means also having a depression at the upper end of said channel and said depression having at least one inclined wall, elongated flexible means extendable between said retaining and mounting means and being freely shiftable in said channel, an abutment at one end of said flexible means preventing said one end from passing through said channel when said flexible means is disposed in said channel, means preventing disconnection of the other end of said flexible means from the other of said retaining and mounting means, a key element in said flexible means and movable into and out of said channel through said opening for interconnecting or disconnecting said retaining and mounting means, said opening and said key element being dimensioned such that only said key element will pass through said opening, and said abutment including a pilot portion extendable into said channel and at least one shoulder engageable with said one of said retaining and mounting means to prevent said abutment from passing through said channel, said pilot portion and said inclined wall of said depression resisting displacement of said abutment from an engaged position with said one of said retaining and mounting means and hence unauthorized opening of said lock when said pilot portion is positioned in said channel.

2. A door lock comprising retaining means adapted to be secured to one of a pair of door and frame members, mounting means adapted to be secured to the other of said members, one of said retaining and mounting means having a channel therein and an opening extending into said channel, elongated flexible means extendable between said retaining and mounting means and being freely shiftable in said channel, said elongated flexible means at the opposite ends thereof preventing disconnection of said ends from said retaining and mounting means, and a key element in said flexible means and having a longitudinally extending portion movable into and out of said channel through said opening to permit interconnection or disconnection of said retaining and mounting means, said key element being dimensioned such that only said portion will pass through said opening and said portion will move through said opening in every rotated orientation thereof about the longitudinal axis of said longitudinally extending portion.

3. The door lock of claim 2, further characterized in that said opening comprises a slot in said one of said retaining and mounting means, and said portion of said key element comprises a straight section thereof.

4. The door lock of claim 3, further characterized in that at least the straight section of said key element is circular in cross section.

5. The door lock of claim 3, further characterized in that said slot includes a divergent portion providing an enlarged entrance into said slot, said enlarged entrance facilitating passage of said portion of said key element through said slot.

6. The door lock of claim 2, further characterized in that said one of said retaining and mounting means includes a tubular portion of substantially circular cross section and providing said channel.

7. The door lock of claim 6, further characterized in that said tubular portion comprises a split sleeve having a gap therein defining said opening.

8. A door lock comprising retaining means adapted to be secured to one of a pair of door and frame members, mounting means adapted to be secured to the other of said members, one of said retaining and mounting means having a channel therein and an opening extending into said channel, elongated flexible means extendable between said mounting and retaining means and being freely shiftable in said channel, said elongated flexible means including means at the opposite ends thereof preventing disconnection of said ends from said retaining and mounting means, and a key element in said flexible means movable through said opening into said channel, said opening and said key element being dimensioned such that only the latter will pass through the former, said channel having at least one substantially planar surface portion providing a convergent exit passage leading toward said opening, said convergent exit passage serving to guide said key element toward said opening and thus facilitate movement thereof through said opening and out of said channel.

9. The door lock of claim 8, further characterized in that said channel means includes a pair of said substantially planar surface portions defining said convergent exit passage.

10. A door lock comprising retaining means adapted to be secured to one of a pair of door and frame members, mounting means adapted to be secured to the other of said members, said retaining and mounting means each having a channel therethrough, one of said retaining and mounting means having an opening extending into said channel, elongated flexible means extendable through the channels in said retaining and mounting means for releasably interconnecting the same, said elongated flexible means being freely shiftable in the channels in said retaining and mounting means and having a key element therein, said opening and said key element being dimensioned such that only said key element will pass through said opening, and an abutment at each end of said flexible means for preventing said ends from passing through the channels in said retaining and mounting means.

11. The door lock of claim 10, further characterized in that the other of said retaining and mounting means includes a recess for receiving and retaining a portion of said flexible means intermediate the ends thereof, whereby the effective length of said flexible means may be varied and likewise the extent to which an associated door may be opened when the lock is in operation.

12. The door lock of claim 11, further characterized in that said flexible means comprises a chain having a series of interconnected links, and said recess comprises a notch in said other of said retaining and mounting means, said notch extending into said channel and being sized to receive and retain at least a portion of a selected one of said links.

References Cited UNITED STATES PATENTS 1,510,562 10/1924 Segal 292-264 X 1,774,351 8/1930 Brand 292--264 1,777,146 9/ 1930 McLaughlin 292-264 2,867,468 1/ 1959 Bugge 292--264 FOREIGN PATENTS 121,972 8/1901 Germany.

3,888 10/ 1878 Great Britain.

MARVIN A. CHAMPION, Primary Examiner E. J. MCCARTHY, Assistant Examiner 

